From 【wiki】
最早1979年 “加拿大定期健康檢查工作隊(duì)”提出該標(biāo)準(zhǔn)【遞減】
I-Evidence?
Evidence from at least one?randomized controlled trial
至少有一個(gè)隨機(jī)對(duì)照試驗(yàn)獲得的證據(jù)
II1-Evidence?
Evidence from at least one well designed?cohort study?or?case control study, i.e. a controlled trial which is not randomized
至少有一個(gè)合理設(shè)計(jì)的群組研究（cohort study）或者案例對(duì)照研究（case control study）, 即一個(gè)可控的非隨機(jī)對(duì)照試驗(yàn)獲得的證據(jù)
II 2-Evidence
Comparisons between times and places with or without the intervention
進(jìn)行過(guò)干預(yù)或非干預(yù)的比較研究荆秦，比較不同的時(shí)間和地點(diǎn)（的案例）獲得的證據(jù)
III-Evidence
Opinions of respected authorities, based on clinical experience, descriptive studies or reports of expert committees.
來(lái)自于權(quán)威機(jī)構(gòu)的觀點(diǎn)肥橙，基于臨床經(jīng)驗(yàn)、描述性研究或?qū)＜椅瘑T會(huì)的報(bào)告
加拿大定期健康檢查工作隊(duì)(CTF) 將他們的提議分為五分制拷况，五檔：
A: Good level of evidence for the recommendation to consider a condition,
基于扎實(shí)的證據(jù)而提議考慮某情況
B: Fair level of evidence for the recommendation to consider a condition,?
基于合理的證據(jù)而提議考慮某情況
C: Poor level of evidence for the recommendation to consider a condition,?
基于較弱的證據(jù)而提議考慮某情況
D: Fair level evidence for the recommendation to exclude the condition,?
基于合理的證據(jù)而提議排除某情況
E: Good level of evidence for the recommendation to exclude condition from consideration.
基于扎實(shí)的證據(jù)而提議排除某情況
1988年美國(guó)預(yù)防服務(wù)工作隊(duì)（United States Preventive Services Task Force(USPSTF)）基于CTF 提出如下標(biāo)準(zhǔn)：
Level I:?
Evidence obtained from at least one properly designed?randomized controlled trial.
至少?gòu)囊粋€(gè)合理設(shè)計(jì)的隨機(jī)對(duì)照試驗(yàn)獲得的證據(jù)
Level II-1:?
Evidence obtained from well-designed controlled trials without?randomization.
從一個(gè)合理設(shè)計(jì)的非隨機(jī)的對(duì)照試驗(yàn)獲得的證據(jù)
Level II-2:?
Evidence obtained from well-designed?cohort?or?case-control?analytic studies, preferably from more than one center or research group.
從一個(gè)合理設(shè)計(jì)的群組研究（cohort study）或者案例對(duì)照研究（case control study）獲得的證據(jù), 最好來(lái)自多于一個(gè)研究中心或研究小組
Level II-3:?
Evidence obtained from multiple time series designs with or without the intervention. Dramatic results in uncontrolled trials might also be regarded as this type of evidence.
從多個(gè)干預(yù)或非干預(yù)的時(shí)間序列獲得的證據(jù), 由于非控制而導(dǎo)致對(duì)照實(shí)驗(yàn)產(chǎn)生劇烈的結(jié)果差異辖所，也歸為此類(lèi)
Level III:?
Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.
來(lái)自于權(quán)威機(jī)構(gòu)的觀點(diǎn)透且，基于臨床經(jīng)驗(yàn)性誉、描述性研究或?qū)＜椅瘑T會(huì)的報(bào)告
Another example of a system for grading evidence is the?Oxford (UK) CEBM Levels of Evidence, Most of the evidence ranking schemes grade evidence for therapy and prevention, but not for diagnostic tests, prognostic markers, or harm. The Oxford CEBM Levels of Evidence addresses this issue and provides 'Levels' of evidence for claims about prognosis, diagnosis, treatment benefits, treatment harms, and screening. The original CEBM Levels was first released in September 2000 for Evidence-Based On Call to make the process of finding evidence feasible and its results explicit. As published in 2009[9]they are?:
1a:
Systematic reviews?(with homogeneity) of randomized controlled trials
由隨機(jī)對(duì)照實(shí)驗(yàn)得到的（同一主題的）綜合觀點(diǎn)
1b:?
Individual randomized controlled trials (with narrow?confidence interval)
單獨(dú)的隨機(jī)對(duì)照實(shí)驗(yàn)（置信區(qū)間小）
1c:?
All or none randomized controlled trials
要么全部杨蛋，要么沒(méi)有任何一個(gè)兜材，是隨機(jī)對(duì)照實(shí)驗(yàn)【我不太理解為什么全部的隨機(jī)對(duì)照實(shí)驗(yàn)是1c】
2a:?
Systematic reviews (with homogeneity) of cohort studies
由群組研究得到的（同一主題的）綜合觀點(diǎn)
2b:?
Individual cohort study or low quality randomized controlled trials (e.g. <80% follow-up)
單獨(dú)的群組研究，或者質(zhì)量較低的隨機(jī)對(duì)照實(shí)驗(yàn)（比如小于80%后續(xù)實(shí)驗(yàn)）【對(duì)于這個(gè)例子我并不理解】
2c:?
"Outcomes" Research; ecological studies
臨床實(shí)效研究逞力；生態(tài)學(xué)研究
3a:?
Systematic review (with homogeneity) of case-control studies
由案例對(duì)比研究得到的（同一主題的）綜合觀點(diǎn)
3b:?
Individual case-control study
單獨(dú)的案例對(duì)比研究
4:
Case series?(and poor quality cohort and case-control studies)
病歷分析（也包括低質(zhì)量的群組和案例對(duì)比研究）
5:
Expert opinion?without explicit critical appraisal, or based on physiology, bench research or "first principles"
無(wú)明確的批判性鑒定的專(zhuān)家意見(jiàn)曙寡，或基于生理學(xué)的實(shí)驗(yàn)室研究或“第一原理（公理）”
In 2011, the Oxford CEBM Levels were redesigned by an international team to make it more understandable and to take into account recent developments in evidence ranking schemes. The Oxford CEBM Levels of Evidence have been used by patients, clinicians and also to develop clinical guidelines including recommendations for the optimal use of phototherapy and topical therapy in?psoriasis[10]?and guidelines for the use of the BCLC staging system for diagnosing and monitoring?hepatocellular carcinoma?in Canada.[11]
鏈接?en.wikipedia.org/wiki/Levels_of_evidence
en.wikipedia.org/wiki/Randomized_controlled_trial
隨機(jī)對(duì)照試驗(yàn)（英語(yǔ)：randomized?controlled?trial，RCT）是一種對(duì)醫(yī)療衛(wèi)生服務(wù)中的某種療法或藥物的效果進(jìn)行檢測(cè)的手段寇荧，特別常用于醫(yī)學(xué)举庶、藥學(xué)、護(hù)理學(xué)研究中揩抡，在司法户侥、教育镀琉、社會(huì)科學(xué)等其他領(lǐng)域也有所應(yīng)用。
隨機(jī)對(duì)照試驗(yàn)的基本方法是蕊唐，將研究對(duì)象隨機(jī)分組屋摔，對(duì)不同組實(shí)施不同的干預(yù)，在這種嚴(yán)格的條件下對(duì)照效果的不同替梨。在研究對(duì)象數(shù)量足夠的情況下钓试，這種方法可以抵消已知和未知的混雜因素對(duì)各組的影響。
“臨床實(shí)效研究”或“實(shí)效研究”（Outcomes Research）副瀑，也有人稱(chēng)之為“效果研究”弓熏，是近年來(lái)在國(guó)際臨床醫(yī)學(xué)領(lǐng)域迅速發(fā)展起來(lái)的新學(xué)科。在許多臨床試驗(yàn)（Clinical Trials）研究中俗扇，凡是有多種疾病硝烂、有多種并發(fā)癥或服用多種藥物的病人常常被排除在外。臨床實(shí)效研究則是研究藥物或其它醫(yī)療措施在非控制的真實(shí)臨床情況下（real world）的效果及經(jīng)濟(jì)和社會(huì)效益等[1]铜幽。臨床試驗(yàn)研究（如RCT）和實(shí)效研究對(duì)于充分了解一個(gè)醫(yī)療產(chǎn)品的實(shí)際醫(yī)療效果、效益和安全性有著同樣重要的意義串稀，只是方法學(xué)上有所不同除抛。
第一原理（英語(yǔ)：First principle），哲學(xué)與邏輯名詞母截，是一個(gè)最基本的命題或假設(shè)到忽，不能被省略或刪除，也不能被違反清寇。第一原理相當(dāng)于是在數(shù)學(xué)中的公理喘漏。最早由亞里斯多德提出。
